In a television picture tube, electrons strike the screen after being accelerated from rest through a potentia?

In a television picture tube, electrons strike the screen after being accelerated from rest through a potential difference of 27000 V. The speeds of the electrons are quite large, and for accurate calculations of the speeds, the effects of special relativity must be taken into account. Ignoring such effects, find the electron speed just before the electron strikes the screen.

OK, so the energy change of a charged particle in an electric field is

E=qV

V is 27kV, q is 1.6E-19C.

This is all converted to kinetic energy - E = .5*mv^2

m is 9.1E-31kg.

Equate the energies.